The present invention relates to a process and apparatus for the combustion of liquid fuels, especially fuel oil Numbers 2 through 4. Further, the present invention relates more particularly to an oil atomizing burner that uses low pressure air as the primary and secondary atomizing medium.
There are known combustion processes and burners by which fuel oils are atomized with air. Prior art burners are not adapted to produce perfect or near perfect combustion. As a result, soot and carbon are formed which has a further detrimental effect on the burner operation as the soot and carbon contaminate the nozzle, combustion chamber and other heat-exchange surfaces. The present invention, by producing complete combustion, eliminates the formation of soot.
One of the more advanced designs for burners prior to the present invention is shown in U.S. Pat. No. 3,362,647 to Davis et al. That patent discloses a burner spray nozzle which utilizes fuel oil under pressure which is thereafter mixed with normally aspirated air. In the present invention, the atomized air is under pressure and the fuel is not. These are burners which do, however, utilize low pressure air for atomization purposes as well as to draw the fuel into the mixing chamber. Such a design is shown in Schreter et al, U.S. Pat. No. 3,254,846. The Schreter patent does not utilize the construction of the present nozzle which has been designed to swirl the fuel-air mixture to increase the atomization process. Further Schreter does not disclose the use of a flame tube or secondary atomization which is utilized by the present invention. Another prior art construction which is of possible interest is disclosed by Graat, U.S. Pat. No. 3,870,456. This prior art reference does not disclose the present invention as it utilizes an entirely different nozzle structure wherein the fuel is under pressure. Further, the Graat reference does not disclose any secondary or tertiary atomization.
The burners disclosed in the above references are similarly deficient when contrasted to the present invention, that is, they do not produce an extremely intense, short-length flame. Further, the present invention is 30% to 40% more efficient than conventional burners. These advantages are the result of combining the flame or mixing tube with secondary and even tertiary atomization, to produce a violet flame with temperatures in excess of 3000.degree. F. without preheating air and/or fuel. Further, the temperature of the flame can be precisely controlled over a complete range while maintaining complete combustion.